Fix a type with class 2 exercise 1
Fix typos with class 2 exercise 1 and 2
Switch the guide to use single-quoted strings by default
Fix typo with class 2 exercise 1 spec
Improve specs for class 2 exercise 4
Improve specs for class 2 exercise 5
Improve specs for class 2 exercise 6
Fix syntax
Merge branch 'master' of https://github.com/codefellows/sea-c21-ruby